Improvement in valves for compound engines



Patented April 11,1876.

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N, PETERS, gHQTO-LITHOGRAPHE WASHINGTON, u c,

UNT ED STATES WILBERD. FISKE AND GEORGE E. n. TOWER, OF BOSTON,MASSACHUSETTS.

PATENT OFFICE.

' IMPROVEMENT IN VALVES FOR COMPOUNDENG'INES;

Specification forming part of Letters Patent No. 175,830, dated April11, 1876; application filed March 13, 1876.

To all whom it may concern Be it known that we, WILBER D. FISKE andGEORGE-B. N. TOWER, of Boston, in the county of Sufiolk and State ofMassachusetts, have invented certain new and useful Improvements inCompound Engines; and we do hereby declare that the following is a full,clear, and-exact description thereof, which will enable others skilledin the art to which it appertains' to make and use the same, referencebeing had to the accompanying drawings, and to the letters of referencemarked thereon, which form a part of this specification.

This invention relates to that class of en gines known as duplex orcompound engines, in which the cylinders are elongated to a suitablelength for the working of a double set of engine-pistons, allowingsufiicient space for the proper expansion of steam at the outer ends ofsaid cylinder; and it consists in a novel arrangement of ports, in whichone valve is made to perform the duty heretofore performed by a seriesof valves, and by which a great saving of power is attained by thediminished amount of friction, and also in first cost by the simplicityof construction and replacement of ports when worn. It also consists inlocating the induction and eduction portsin such a manner that a doubleset of live-steam and exhaust ports is provided for each end of thecylinder, and all the steam required to operate the pistons in saidcylinder ends is made to pass through one valve common to both, saidsingle valve answering the. fourfold purpose of admitting to, andexhausting from, the double-sided piston in each end of the cylinder thelive steam impinging upon one end of the piston in one end of thecylinder, while the exhaust from the live steam -ot the other end ofsaid cylinder is impingpacking-rings, and the two ends connected by atrunk common to both cylinder ends, each containing an independentpiston-head, none of which we claim, nor the compound operating,intricate, complicated,.complex system of valve mechanism, so well knownto this class of engines, which require a large portion of the power-ofthe engine to successfully operate them, owing to the great friction,and also a large quantity of lubricants to keep them in a smooth Workingcondition, as well as their costly construction.

To obviate these. objections, andsimplify the working parts, is what Wedesire to accomplish by our invention; but what we do claim as new,useful,.and important we will now proceed to describe, and refer to theaccompanying drawing, which forms part of our description andspecification.

Fig. l illustrates a longitudinal vertical section Fig. 2, an invertedplan view of the face of the valve.

By referring to Fig. 1, it will be observed that it is a longitudinalvertical section' through the double cylinder, pistons, trunk,

valve, valve-chest, and induction and educ tion ports, in which is seen,by means of an arrow, the steam entering the live-steam port from thesteam-chest, passing down to, and impinging upon, the trunk end of thepistonhead, the area of which is near or about onehalf the area of theother or expansion side,

When this piston is near the end of its stroke, and live steam enteringthe opposite port on the other side of the valve to the trunkside of theother piston, the exhaust steam from the first or trunk side istransferred to the expansion end of the cylinder through the same port,whereit expends its remaining power, and thence is exhausted into theatmosphere or condenser, and so on alternating during the operation ofthe engine, and repeating the same operation in the opposite end of thecylinder.

The letters on the drawings indicate the following parts: A is thecylinder, provided with the usual heads and the inner annular projection0, which is also provided with the usual metal packing. This cylinder isalso constructed with a hollow hot air or steam space, H, around itsperiphery, forming a jacket, the

object of which is to prevent the radiation of heat, and thereby theprevention of the condensation of steam. B and B represent the twopistons with their packing, both of ordinary construction. E representsthe trunk, which connects the two piston-heads, the said trunkpresenting a smooth outer surface, and parallel its entire length, andwhich works through the inner annular projection, while being packed bythe packing-rings in the face of said projection. O is theconnecting-rod, the trunk part of which is smaller in diameter 7 thanthe stufling-box end, and which, with the trunk, also serves to connectthe two pistons,

passing entirely through piston-head B and E, and secured in the usualmanner to piston-head B. D represents the main valve, which is a doubleported one, with divisions i, and communicating with two sets of portsin the face of the cylinder. Said valve, while in communication with thelive-steam port of one piston, is also in communication with the exhaustof the other, tranferring the steam to be expanded to its properdestination, and at the same time carrying off the spent steam, whichhas already been worked twice. This compound duplex valve and itscorresponding ports form the gist of my invention, the oper: ration ofwhich has been before explained. F is the valve-stem, which is operatedby positive means, viz.: by a tappet-arm, d, on the main piston-rod G,and kept in position by a guide-piece, h, all operating smoothly, and sosimple that any person of ordinary intelligence can manipulate it.

It will be seen that it is made up of but very few pieces, requiringonly ordinary mechanical skill in its construction, all of which is ofthe greatest importance, as is well known none but first-classmechanicalskill can build, repair, or manipulate the complicated enginesof this character, such skill, in many places where there are noworkshops, being very scarce, and when as it often does occur that suchskill haste be sent for along distance, during which time the wholeworks are stopped, the consequence being ruinous.

Having now described our invention, and its "mode of construction andoperation, what we claim as new, and desire to secure by Letters Patent,is

The combination, in compound or duplex engines, and in whichdifferential pistons are used as a medium of motive power, of thefourported single valve D, and the double livesteam and exhaust ports oneach side of a single valve-seat, by which a compound engine is operatedin each end of the cylinder,

substantially as herein described.

In testimony that we claim the foregoing as our own invention we affixour signatures in presence of two witnesses.

'WILBER D. FIsKE. GEORGE B. N. TOWER.

Witnesses:

JOHN D. ELDRIDGE, HENRY K. TERRY.

